1. Field of the Invention
This invention relates to a novel microorganism belonging to Bacillus thuringiensis serovar japonensis, to an insecticide derived from this novel microorganism, and to DNA coding for the insecticide.
2. Description of the Related Art
The reported activity spectrum of B.t. covers insect species within the order Lepidoptera, many of which are major pests in agriculture and forestry. The activity spectrum also includes the insect order Diptera, which includes mosquitos and black flies. See Couch, T. L. (1980) "Mosquito Pathogenicity of Bacillus thuringiensis var. israelensis," Developments in Industrial Microbiology 22:61-76; Beegle, C. C., (1978) "Use of Entomogenous Bacteria in Agroecosystems," Developments in Industrial Microbiology 20:97-104. Krieg et al. (1983) Z. ang. Ent. 96:500-508, describe a B.t. isolate named Bacillus thuringiensis var. tenebrionis, which is reportedly active against two beetles in the order Coleoptera. These are the Colorado potato beetle, Leptinotarsa decemlineata, and Agelastica alni.
In European Patent Application 0 202 739 there is disclosed a novel B.t. isolate active against Coleoptera. It is known as B. thuringiensis var. san diego (B.t.s.d.). U.S. Pat. No. 4,966,765 discloses the coleopteran-active Bacillus thuringiensis isolate B.t. PS86B1. European Patent Application 0 337 604 also discloses a novel B.t. isolate active against Coleoptera.
Coleopteran-active B.t. strains can be used to control foliar-feeding beetles. The Colorado potato beetle (Leptinotarsa decemlineata), for example, is susceptible to the delta-endotoxin of B.t.s.d. and larvae are killed upon ingesting a sufficient dose of spore/crystal preparation on treated foliage. Strain cells among Bacillus thuringiensis serovar japonensis are known to produce insecticidal proteins that kill lepidopteran larvae. However, none of the strain cells among japonensis are known to produce toxin proteins other than the insecticidal proteins that kill lepidopterous larvae. Thus, no such strain cells have been available for use as an insecticide to kill insects other than lepidopterans. Furthermore, Bacillus thuringiensis san diego and Bacillus thuringiensis tenebrionis have no insecticidal effect on larvae of Anomala cuprea Hope, which are very destructive to firewood, taro, sweet potato, peanut, and the like.
The current inventors have found a new type of microorganism belonging to Bacillus thuringiensis serovar japonensis that produces insecticidal proteins to kill coleopterous larvae as distinct from lepidopterous larvae.